An example of stubbing with Mockito (with TestNG)

AddressInputQueue.java

package com.pillartechnology.mail;

public class AddressInputQueue {

	public String next() {
		return null; //TODO: not implemented yet.
	}
	
}

AddressSplitter.java

package com.pillartechnology.mail;

import static java.util.Arrays.*;
import java.util.List;

public class AddressSplitter {

	private AddressInputQueue addressInputQueue;
	
	public List<String> split() {
		return asList(addressInputQueue.next().split(","));
	}

}

AddressSplitterTest.java

package com.pillartechnology.mail;

import static org.hamcrest.MatcherAssert.*;
import static org.hamcrest.Matchers.*;
import static org.mockito.Mockito.*;

import java.util.List;

import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

public class AddressSplitterTest {

	@InjectMocks private AddressSplitter subject = new AddressSplitter();
	
	@Mock private AddressInputQueue addressInputQueue;
	
	@BeforeMethod(alwaysRun=true)  
	public void injectDoubles() {
		MockitoAnnotations.initMocks(this); //This could be pulled up into a shared base class
	}
	
	@Test
	public void splitsAddressesByComma() {
		when(addressInputQueue.next()).thenReturn("jim@weirich.com,kent@beck.com");
		
		List<String> result = subject.split();
		
		assertThat(result,hasItems("jim@weirich.com","kent@beck.com"));
	}
	
}

Can you include the versions of the tools you are using? Thanks

Be aware that TestNG does not recreate your test class for multiple test methods in the same test class (and, unfortunately, Mockito wont recreate the @InjecktMocks objects if the instances are not null), which will lead to your mocks / tested objects not being recreated for different test methods, even though the initMocks call is in a @BeforeMethod-annotated method. I know this example only has one test method, but people using this as a starting point will quickly fall for this. See also: https://code.google.com/p/mockito/issues/detail?id=304

When I was using mockito without @mock, the verify() calls would count up for every @test annotated method. The only wayw to fix this problem was to use this gist, or new up the mock in the @BeforeMethod (which didn't seem reasonable). I like this default behavior better, where the mock isn't expected to persist state from previous tests.

Thank you!

Thanks, very helpful.